Cutter chain



Aug. 4, 1925. 1,548,745

T. E. PRAY CUTTER CHAIN Filed June 16g l925 Patented Aug. 4, 1925.

FMC.

THOMAS E. PRAY, OF CHICAGO, ILLINOIS, ASSIGNOR TO GOODMAN MANUFACTURINGCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CUTTER CHAIN.

Application lcd June 16,

To all whom t 'may concern.'

Be it known that I, THOMAS E. PRAY. a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Cutter Chains, of which thefollowing is a specification.

This invention relates to improvements in cutter chains for miningmachines and has for its principal object to provide a simple anddurable construction of chain block and cutter bit.

More specifically, the object of my invention is to provide an improvedconstruction and arrangement of clamping means for the cutter bit in ablock of the type disclosed in my prior applications bearing SerialNumber 431,250, filed December' 16` 1920, and Number 600,499, filedNovember 13, 1922, with particular reference to the clamping device forthe bit.

The invention may be best understood by reference to the accompanyingdrawings in which:

Figure 1 is a side view of a chain block with the bit in' place.

Figure 2 is an end view of the chain showing it in position in a cutterhead of a mining machine.

Figure 3 is a perspective view of an improved bit gripping elementforming a part of my invention.

Figure 4 is a detail view of the clamping element for the bit with aportion thereof broken away.

In the drawings I have shown a cutter chain for mining machines which ismade up of a series of chain blocks 1, 1, pivotally connected togetherby a series of suitable straps 2, 2. The chain in use is an endlesschain that passes about a driving sprocket and works in a grooved cutterhead 7. The cutter head is preferably provided at the top and bottomwith guideways 3, 3, in which the restraining lips 4 and 5 on the blocksand straps are retained. The blocks are provided with cutter bits 6, 6.The cutter chain is made up of a series of such chain blocks whichextend at various angles from the grooved cutter head, as shown inFigure 2.

The cutter bit 6 is preferably of iiat bar stock having a substantiallyuniform crosssection intermediate its ends and is inclined 1923. SerialNo. 645,762.

forwardly and outwardly in a bit receiving aperture 9, formed in thebody of the block.

Means for securing the bit in the block comprise a clamping member 14which lits in an aperture 15 extending lengthwise through the outerportion of the block at substantially right angles to the bit 6. Thisaperture is preferably made of substantially uniform cross-sectionthroughout its length, as for example, it may be a drilled hole in whichthe clamping member 14 is fitted. In the form shown in the drawings, theforward end of the clamping member 14 is adapted to extend through andbe substantially Hush with the forward face 8 of the block, as isdisclosed in my co-pending application bearing Serial Number 600,499,although my present invention does not relate to this feature, and theclamping member 14 may also stop short of the forward face 8 of theblock, as in the form disclosed in another co-pending applicationbearing Serial Number 431,250.

T he specific feature of novelty forming the subject matter of thepresent invention relates to the provision of a gripping device to beused in conjunction with a clamping member 14 so as to securely hold thebit 6 in place in the block. One of the difficulties in the operation ofcutter chains having removable bits therein is that of securing thebits' in the blocks so that they cannot work loose while in operation.The

clamping pressures which may be exerted by screw devices of the ordinarykinds have not been satisfactory for this purpose where the engagingsurface of the clamping device is a plane surface. It therefore has beenfound necessary in devices of this character to provide a grippingdevice preferably of relatively hard material, such as tool steel,having roughened surfaces adapted to afford a firm grip upon the bit. Inthe present invention I provide an improved form of gripping devicecomprising a threaded member 20, preferably'of special steel, heattreated to a high degree of hardness. A suitable slot 21 of the usualkind may be formed in the threaded member 20, as shown. This grippingdevice is screwed into the clamping member 14 at the forward end of thebit receiving` aperture or recess 16. This aperture 16 is adapted to bepositioned in alignment with the bit receiving aperture 9 in the block,so as to receive the bit 6 therethrough. The grip ping. member 2O isscrewed. into theclamping member so that its axis Will be parallel to,the front Vsurface or" the` bit with vvhich it is to be engaged. Therearmost.-

threaded portion of the gripping member is arranged to extend into therecess 16 as shown in Figure 4:.

The rear end of they clamping member is provided With a threaded portion18 adapted toextend beyond the'rear Jrace of the'block and having a nutI9 thereon. Means are provided for preventing the rotation'of theclamping member, such as a pin 22 extending through the block andengaging a flat tened surface 23 formed on the clamping member. The pin22 is also adapted. to engage a shoulder 2i on the clamping member toretain the latter in the block.

In the improved form `herein disclosed it Will be seen that the clampingmember 14 is provided' with an extremely simple form of gripping devicewhich may be readily made up from. threaded material and easilyassembled in the clamping Threads provide the necessary grip to the bitalong the entirelength ofthe gripping device and being of relativelyhard material effectively resist Wear incident to it. However, as thethreads become VWorn they gripping memberV may be rotated either in onedirection or the other so as to present a new gripping surface' to thebit thereby Vprovid'- ing several. changes in the operating surface withthe simplest kinder an adjustment, and Without necessitating replacementof the grippingdevice. Inflthe form shown, adjustment of`` the grippingdevice may be maden Without removing the clamping member 14 from theblock by simply loosening andwithdraiving the bit 6 from its aperture 9Vand' then by shiftingthe clamping device to the rear, itmaybe broughtinto member. Y

position Where a screwdriver may be insertedf through the b1t-rece1vingaperture 9 to engage the grlppmg member 20 and ro- Y tate it.

Y I claim as my invention: y

l. In combination with a cutter chain block for mining machines having abit receiving aperture therein, a bit, a clamping member arrangedtransversely of said bit receiving aperture and having means adj ustablefrom the rear end of said block for drawing said clamping memberrearwardly tok secure the bit in bearing engagement in saidibitreceiving aperture, and a bitgripping device comprising a plug ofrelatively hard material threaded transversely in said clamping memberwith the threaded p0rtion along one side in position to engage the bit.

2. In combination with a cutter chain block for mining machines having abit receivi'ngl aperture therein, a bit, a clamping member arrangedtransversely of said bit receiving aperture and having means adjustablefrom the rear end of said blockfor drawing said clamping memberrearwardly to secure the bit in bearing engagement in said bit receivingaperture, a bitgripping device comprising a plug ofV relatively hardmaterial threaded transversely in said clamping member with the threadedp0rtion along one side in position to engage the bit, and means securingsaid clamping member tor limited longitudinal movement in said block,said last named means affording THOMAS E. PRAY. y

